Download or read book Static and Fatigue Analysis of Wind Turbine Blades Subject to Cold Weather Conditions Using Finite Element Analysis written by Patricio Lillo and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Canada has aggressive targets for introducing wind energy across the country, but also faces challenges in achieving these goals due to the harsh Canadian climate. One issue which has received little attention in other countries not experiencing these extremes is the behaviour of composite blades in winter conditions. The scope of the work presented is to analyze the static stresses and fatigue response in cold climates using finite element models of the blade. The work opens with a quantification of the extremes of cold experienced in candidate Canadian wind turbine deployment locations. The thesis then narrows its focus to a consideration of the stresses in the root of the composite blades, specifically two common blade-hub connection methods: embedded root carrots and T-bolts. Finite element models of the root are proposed to properly simulate boundary conditions, applied loading and thermal stresses for a 1.5MW wind turbine. It is shown that the blade root is strongly affected by the thermal stresses caused by the mismatch and orthotrophy of the coefficients of thermal expansion of the blade root constituents. Fatigue analysis of a blade is then presented using temperature dependent material properties including estimated fatigue coefficients. It was found that the natural frequencies of a 1.5MW wind turbine blade are not significantly altered at cold temperatures. Additionally, cold temperatures slightly increase stresses in the composite blade skin when the blade is loaded, due to an increase in stiffness. Cold temperatures also lead to higher cyclic flapwise bending moments acting on the blade. However, this increase was found not to affect the lifetime fatigue damage. Finally, it was found that the cold climate as seen in Canada improves the fatigue strength of the saturated composite materials used in the blade. The predicted fatigue damage of the triaxial fabric and the spar cap layers in cold climates was therefore predicted to be half that of the fatigue damage at room temperature. This is caused solely by the temperature dependence of the fatigue coefficient b which requires further experimental verification to validate the numerical results of the current study.
Download or read book Static and Fatigue Analysis of Wind Turbine Blades Subject to Cold Weather Conditions Using Finite Element Analysis written by Patricio Andres Lillo Gallardo and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Comparative Study of Static and Fatigue Behaviors for Various Composite Orthotropic Properties for a Wind Turbine Using a Coupled Fem Bem Method written by Adam Chehouri and published by . This book was released on 2014-01 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master's Thesis from the year 2013 in the subject Engineering - Mechanical Engineering, grade: 4.06/4.5 GPa, language: English, abstract: In the wind industry, the current trend is towards building larger and larger turbines. This presents additional structural challenges and requires blade materials that are both lighter and stiffer than the ones presently used. This work is aimed to aid the work of designing new wind turbine blades by providing a comparative study of different composite materials. A coupled Finite-Element-Method (FEM) - Blade Element Momentum (BEM) code was used to simulate the aerodynamic forces subjected on the blade. The developed BEM code was written using LabView allowing an iterative numerical approach solver taking into the consideration the unsteady aerodynamic effects and off -design performance issues such as Tip Loss, Hub Loss and Turbulent Wake State therefore developing a more rational aerodynamic model. For this thesis, the finite element study was conducted on the Static Structural Workbench of ANSYS, as for the geometry of the blade it was imported from a previous study prepared by Cornell University. Confirmation of the performance analysis of the chosen wind turbine blade are presented and discussed blade including the generated power, tip deflection, thrust and tangential force for a steady flow of 8m/s. The elastic and ultimate strength properties were provided by Hallal et al. The Tsai- Hill and Hoffman failure criterions were both conducted to the resulting stresses and shears for each blade composite material structure to determine the presence of static rupture. A progressive fatigue damage model was conducted to simulate the fatigue behavior of laminated composite materials, an algorithm developed by Shokrieh. It is concluded that with respect to a material blade design cycle, the coupling between a finite element package and blade element and momentum code under steady and static conditions can be useful. Especially whe
Download or read book Advances in Composite Wind Turbine Blades A Comparative Study written by Adam Chehouri and published by Anchor Academic Publishing (aap_verlag). This book was released on 2014-03-19 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the wind industry, the current trend is towards building larger and larger turbines. This presents additional structural challenges and requires blade materials that are both lighter and stiffer than the ones presently used. This study is aimed to aid the work of designing new wind turbine blades by providing a comparative study of different composite materials. A coupled Finite-Element-Method (FEM) - Blade Element Momentum (BEM) code was used to simulate the aerodynamic forces subjected on the blade. For this study, the finite element study was conducted on the Static Structural Workbench of ANSYS, as for the geometry of the blade it was imported from a previous study prepared by Cornell University. Confirmation of the performance analysis of the chosen wind turbine blade is presented and discussed including the generated power, tip deflection, thrust and tangential force for a steady flow of 8m/s. A homogenization method was applied to derive the mechanical properties and ultimate strengths of the composites. The Tsai-Hill and Hoffman failure criterions were both conducted to the resulting stresses and shears for each blade composite material structure to determine the presence of static rupture. A progressive fatigue damage model was conducted to simulate the fatigue behavior of laminated composite materials, an algorithm developed by Shokrieh.
Download or read book Structural Analysis of Composite Wind Turbine Blades written by Dimitris I Chortis and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concerns the development of novel finite elements for the structural analysis of composite beams and blades. The introduction of material damping is also an important aspect of composite structures and it is presented here in terms of their static and dynamic behavior. The book thoroughly presents a new shear beam finite element, which entails new blade section mechanics, capable of predicting structural blade coupling due to composite coupling and/or internal section geometry. Theoretical background is further expanded towards the inclusion of nonlinear structural blade models and damping mechanics for composite structures. The models effectively include geometrically nonlinear terms due to large displacements and rotations, improve the modeling accuracy of very large flexible blades, and enable the modeling of rotational stiffening and buckling, as well as, nonlinear structural coupling. Validation simulations on specimen level study the geometric nonlinearities effect on the modal frequencies and damping values of composite strips of various angle-ply laminations under either tensile or buckling loading. A series of correlation cases between numerical predictions and experimental measurements give credence to the developed nonlinear beam finite element models and underline the essential role of new nonlinear damping and stiffness terms.
Download or read book Offshore Wind Farms written by Chong Ng and published by Woodhead Publishing. This book was released on 2016-03-03 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offshore Wind Farms: Technologies, Design and Operation provides the latest information on offshore wind energy, one of Europe's most promising and quickly maturing industries, and a potentially huge untapped renewable energy source which could contribute significantly towards EU 20-20-20 renewable energy generation targets. It has been estimated that by 2030 Europe could have 150GW of offshore wind energy capacity, meeting 14% of our power demand. Offshore Wind Farms: Technologies, Design and Operation provides a comprehensive overview of the emerging technologies, design, and operation of offshore wind farms. Part One introduces offshore wind energy as well as offshore wind turbine siting with expert analysis of economics, wind resources, and remote sensing technologies. The second section provides an overview of offshore wind turbine materials and design, while part three outlines the integration of wind farms into power grids with insights to cabling and energy storage. The final section of the book details the installation and operation of offshore wind farms with chapters on condition monitoring and health and safety, amongst others. - Provides an in-depth, multi-contributor, comprehensive overview of offshore technologies, including design, monitoring, and operation - Edited by respected and leading experts in the field, with experience in both academia and industry - Covers a highly relevant and important topic given the great potential of offshore wind power in contributing significantly to EU 20-20-20 renewable energy targets
Download or read book Ground Based Radar in Structural Design Optimization and Health Monitoring of Stationary and Rotating Structures written by Francis Xavier Ochieng and published by Springer Nature. This book was released on 2023-06-10 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a practical application for using ground-based radar (GBR) as a remote (non-contact) sensor for structural health monitoring (SHM) in the development of sustainable and robust stationary and rotating structures, such as beam-like bridges, towers, wind turbines, and hydropower turbines. It integrates cutting-edge research into an easy-to-understand approach for non-radar and monitoring specialists, building on the methods and theory of working with radar systems, SHM frameworks, GBR signal processing, and validation techniques. All aspects of in-field monitoring and use during the design and testing of structures are covered, including data acquisition and processing, damage detection techniques, and damage prognostic techniques. The book is a hands-on reference that provides critical information on GBR for practitioners, university instructors, and students involved in structural design, optimization, and health monitoring of stationary and rotating structures.
Download or read book Advances in wind turbine blade design and materials written by D.J. Lekou and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chapter discusses the topic of probabilistic analysis of wind turbine blades. First, structural analysis models, the definition of ‘failure’ and the treatment of random variables will be explored, focusing on the challenges involved in a probabilistic design depending on the choices made during each step. Next, the various probabilistic methods (Monte Carlo method, first-order reliability method, Edgeworth expansion method, response surface method) will be described. Issues arising out of the use of composite material structures, in applications such as wind turbine blades, as well as other aspects relating to wind energy applications will be highlighted, and techniques will be discussed through examples.
Download or read book Analysis of the 2 5m PowerOn Wind Turbine Blade for Static Strength and Fatigue Life Using Finite Element Methods written by Christopher Allan Stanley and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Wind Turbine Blade Design and Materials written by Povl Brondsted and published by Elsevier. This book was released on 2013-10-31 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy is gaining critical ground in the area of renewable energy, with wind energy being predicted to provide up to 8% of the world's consumption of electricity by 2021. Advances in wind turbine blade design and materials reviews the design and functionality of wind turbine rotor blades as well as the requirements and challenges for composite materials used in both current and future designs of wind turbine blades.Part one outlines the challenges and developments in wind turbine blade design, including aerodynamic and aeroelastic design features, fatigue loads on wind turbine blades, and characteristics of wind turbine blade airfoils. Part two discusses the fatigue behavior of composite wind turbine blades, including the micromechanical modelling and fatigue life prediction of wind turbine blade composite materials, and the effects of resin and reinforcement variations on the fatigue resistance of wind turbine blades. The final part of the book describes advances in wind turbine blade materials, development and testing, including biobased composites, surface protection and coatings, structural performance testing and the design, manufacture and testing of small wind turbine blades.Advances in wind turbine blade design and materials offers a comprehensive review of the recent advances and challenges encountered in wind turbine blade materials and design, and will provide an invaluable reference for researchers and innovators in the field of wind energy production, including materials scientists and engineers, wind turbine blade manufacturers and maintenance technicians, scientists, researchers and academics. - Reviews the design and functionality of wind turbine rotor blades - Examines the requirements and challenges for composite materials used in both current and future designs of wind turbine blades - Provides an invaluable reference for researchers and innovators in the field of wind energy production
Download or read book Advances in wind turbine blade design and materials written by F. Mølholt Jensen and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the current and future trends in wind turbine blade structural design process is presented. The main design principles and failure mechanisms of blades in operation are assessed and explained through an industry point of view, in a realistic manner. A number of failure modes which are not addressed sufficiently in the certificate guidelines are presented. An example on how to use the new design philosophy is presented. The manufactured prototype is a 44m long load carrying spar and the weight is reduced by 40%.
Download or read book Advances in wind turbine blade design and materials written by J.F. Mandell and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter explores the influence of resin and reinforcing fabric variations on the fatigue sensitivity for a wide range of typical blade laminates reported recently in the SNL/MSU/DOE database. Test results are presented for static and fatigue property variations with resin type, reinforcing fabric construction and weight, fiber content and laminate construction. Critical resin/fabric interactions and damage mechanisms are identified. The effects of resin and fiber type are also explored for material transitions at ply drops, where ply delamination is the dominant damage.
Download or read book Non linear Ultimate Limit State Analysis of a Wind Turbine Blade written by Malo Rosemeier and published by . This book was released on 2013-09 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masterarbeit aus dem Jahr 2013 im Fachbereich Ingenieurwissenschaften - Energietechnik, - (Technical University of Denmark), Sprache: Deutsch, Abstract: A geometrically non-linear structural response of a 34 m wind turbine blade under flap-wise loading was compared with a linear analysis to show the need of non-linear analysis in wind turbine blade design. Non-linear effects revealed from a numerical finite element model were compared with an analytical plate model of the cap under compression load. The plate model was subjected to a transversal load due to the non-linear Brazier effect, and to in-plane loading to reveal the local cap displacement and the buckling resistance respectively. Focus was on the verification of the characteristic and design resistance in the ultimate strength and stability limit state. For the design resistance, an analysis due to the lowest GL requirements was used and compared with the results of a non-linear approach proposed by GL that required the application of an imperfection to the model. The way to apply an imperfection due to EUROCODE seemed more realistic compared with GL's approach. Numerous simulations revealed the requirement of non-linear analysis methods in design of wind turbine blades. A linear analysis due to the lowest GL requirements yielded less conservative results than a non-linear approach proposed by GL. That led to the fact, that the investigated blade designed after the lowest requirements would pass the certification, whereas the same blade design verified with the non-linear approach would not. The non-linear structural response was significantly dependent on the scaling of an applied imperfection.
Download or read book Analysis of SNL MSU DOE Fatigue Database Trends for Wind Turbine Blade Materials written by and published by . This book was released on 2010 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents an analysis of trends in fatigue results from the Montana State University program on the fatigue of composite materials for wind turbine blades for the period 2005-2009. Test data can be found in the SNL/MSU/DOE Fatigue of Composite Materials Database which is updated annually. This is the fifth report in this series, which summarizes progress of the overall program since its inception in 1989. The primary thrust of this program has been research and testing of a broad range of structural laminate materials of interest to blade structures. The report is focused on current types of infused and prepreg blade materials, either processed in-house or by industry partners. Trends in static and fatigue performance are analyzed for a range of materials, geometries and loading conditions. Materials include: sixteen resins of three general types, five epoxy based paste adhesives, fifteen reinforcing fabrics including three fiber types, three prepregs, many laminate lay-ups and process variations. Significant differences in static and fatigue performance and delamination resistance are quantified for particular materials and process conditions. When blades do fail, the likely cause is fatigue in the structural detail areas or at major flaws. The program is focused strongly on these issues in addition to standard laminates. Structural detail tests allow evaluation of various blade materials options in the context of more realistic representations of blade structure than do the standard test methods. Types of structural details addressed in this report include ply drops used in thickness tapering, and adhesive joints, each tested over a range of fatigue loading conditions. Ply drop studies were in two areas: (1) a combined experimental and finite element study of basic ply drop delamination parameters for glass and carbon prepreg laminates, and (2) the development of a complex structured resin-infused coupon including ply drops, for comparison studies of various resins, fabrics and pry drop thicknesses. Adhesive joint tests using typical blade adhesives included both generic testing of materials parameters using a notched-lap-shear test geometry developed in this study, and also a series of simulated blade web joint geometries fabricated by an industry partner.
Download or read book Advances in wind turbine blade design and materials written by A.P. Vassilopoulos and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue life prediction of wind turbine rotor blades is a very challenging task, as blade failure is led by different failure types that act synergistically. Inherent defects like wrinkles, fiber misalignments and voids, that can be introduced during fabrication, can constitute potential damage initiation points and rapidly develop to failure mechanisms like matrix cracking, transverse-ply cracking, interface cracking, debonding, fiber breakage, etc. Different methods have been established to address this problem, some based on phenomenological and others on actual damage mechanics modeling. This chapter aims to provide an overview of fatigue life modeling and prediction methodologies for the composite materials and structural composite elements that compose a wind turbine rotor blade under complex loading conditions.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Advances in wind turbine blade design and materials written by L. MISHNAEVSKY and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the micromechanics of materials methods and approaches that can be used for the modelling of wind turbine blade composites is given in this chapter. Using the various modelling methods reviewed here, the strength, stiffness and lifetime of composite materials can be predicted and the suitability of different groups of materials for applications in wind turbine blades can be analysed. The effects of interface and matrix properties, fibre clustering and nanoreinforcement on the strength and lifetime of composites are studied in a number of simulations, and some examples of the analysis of microstructural effects on the strength and fatigue life of composites are provided.
